1. Field of the Invention
This invention relates to a telescoping and locking assembly of tubular members and in particular to an extendible, locking tube assembly useful with carpet stretchers and the like.
2. Brief Statement of the Prior Art
My prior U.S. Pat. Nos. 3,693,936 and 3,791,624 disclose various extendible, telescoping tube assemblies for carpet stretchers. In the latter patent, I have disclosed and claimed an extendible and locking telescoping assembly of tubular members which can be connected in the otherwise conventional pole assembly used with carpet stretchers. A commercial embodiment of the patented device has been marketed under the designation Magic-Lok to the carpet installation industry.
The patented device is relatively complex having a completely, internally-contained locking collar which is located at the tail end of the assembly and includes an internal push tube linked to an external release lever to move the collar from its locking position. The complexity of this device results in a relatively high cost of manufacture and maintenance particularly since the device cannot be readily disassembled in the field but must be returned to the factory for repair and adjustment. Additionally, the complete containment of the locking collar within the inner tube compromises the lever advantage of the locking collar and limits the maximum loading permitted on the assembly. Finally, the device requires that the operator employ both hands to release and retract the assembly and this usually requires that the operator shift his position from that assumed in operation of the carpet stretcher.